Extension-leg for compasses.



L. PRICE.

EXTENSION LEG FOR COMPASSES.

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Patented Aug. 13, 1918.

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LOUIS PRICE, 0:? BROOKLYN, new YORK.

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Specification of Letters Patent.

Patented Aug. 13, 1918.

Application filed August 2, 1917. Serial No. 184,079.

To all whom it may concern: 1

Be it known that I, Louis PRICE, a citizen of the United States, and a resident of Brooklyn, inthe county of Kings and State of New York, have invented a certain new and useful Improvement in Extension-Legs for Compasses, of which the following is a specification. i t

The present invention relates to drafting instruments, and more particularly to an improved extension leg for use with compasses.

An object of the presentinvention is to provide an extension leg of such construction that the same may be applied to an ordinary compass when it isdesired to draw relatively large circles and the like, and

when a beam compass is not at hand, and a where the nature of the work precludes the use of a beam compass; 'an extension leg whichis longitudinally adjustable to adapt the ordinary compass for drawing circles and curves at various radii; an extension leg which is substantially the same size and appearance as the ordinary extension leg; which may be economically manufactured; and which may be quickly and easily adj ustedto the parts of the compass and also adjusted for curves of various radii.

The above, and various other objects and advantages of this invention will be inpart described, and in part understood, from the following detailed description of the present preferred embodiment, the same being illustrated in the accompanying. drawing wherein: 1

Figure 1 is a side elevation of an ordinary compass having an extension leg constructed accordingto the presentinvention applied thereto, and being partly extended.

Fig. 2 is a detail perspective View, partly broken away, of one of the'sliding sections of the extension leg. p

Fig. 3 is an edge view of the extension leg of this invention collapsed or folded.

Fig. 4 is a transverse section takensubstantially on the line 11 of Fig; 3, being enlarged nd looking in the direction indicated by the arrows. a a i a Fig. 5 is a transverse section through the body portion of the extension legwith the slides removed therefrom.

Fig. 6 is a transverse section through one ofthe slides employed.

Fig. 7 is a transverse sectionthrough a modified form of extension leg constructed according to the present invention.

Referring to this drawing, A and B designate the legs of an ordinary compass which are pivotally connected together at their upper ends in the yoke C. The leg A is provided in the usual manner with the anchoringwsection D, and the leg B is provided. upon. its lower end with a socket E into which is detachably fitted the stem F of the usualscriber leg As shown, the anchoring sections or le s B and G are provided at their upper ends with hinge joints by means of which the sections D and G may be adjusted in substantially parallel relation irrespective of the angle between the legs A and B.

The extension leg of this invention comprises a bar or body part 10'having openings 11 and 12 in the opposite sides thereof which may be of dove-tail form, as shown in Fig. 5, or which may be rectangular, as shown inFig. 7 These openings 11 and 12, or their substantial equivalent, form guides at the opposite sides ofthe bar 10 which extend longitudinally thereof, and preferably throughout the entire length of the bar. The bar 10 carries in the guides 11 and 12 a pair of slides 13 and 1.4. These slides 13 and 1 4. are in the form of relatively thin bars whichcorrespond in form at their opposite longitudinal edges to the guides 11 and 12 for the purpose of retaining the bars in longitudinal alinement with the body bar 10, and in the form shown in Figs. 5 and 6, for retaining the slides 13 and 14 from displacement from the opposite sides of the body bar 10. The slides 13 and 14: are

adapted to move longitudinally in the guides 11 and 12, and for the purpose of securing the slides in adjusted positions, the body bar 10 is provided near its opposite lateral edges with thumb screws 15 threaded through preferably one side of the bar 10, and which .are adapted to bind against the adjacent .edgeportions. of the slides 13 and 14:.

The slide 13 is provided upon one end .ing the scriber section G and the latter is 7 secured to the leg extension. This knob 19 section G of the compass and insert the stem is also adapted to be used in sliding the section 14 in the body bar 10, and in also sliding the body bar 10 upon the section 13, which latter is adapted to be secured and anchored to the leg B of the compass.

The body bar B is preferably provided, at leastupon one side, with a longitudinal row of graduations 20 by means of which certain predetermined positions of adjustment of the slides 13 and 14 may be found.

The graduations or scale 20 admit of the forming of arcs on radii of different relative lengths. Then the compass is used with the'extension leg of this invention applied thereto, the extension leg is dis osed horizontally with the members D and extending vertically. The extension leg is first adjusted without reference to the scale 20 unless the scale 20 is proportioned according to the distances between the members D and G. After the are or circle is drawn, the extension leg may then be adjusted by usin the scale 20 to move the members B and toward or from each other to form a circle or arc on a radii which is either smaller or larger than the one first formed. The scale 20 is preferably divided into standard unit of measurements and fractions thereof, such as inches, and by such means the relative length ofthe are may be quickly and accurately found.

In the modified form shown in Fig. 7 the bodybar 10 has guide slots in its opposite sides of rectangular form adapted to receive the slides 13 and 14 of corresponding cross-sectional form.

In theuse of the improved extension leg, it is only necessary to remove the scriber 17 of the extension leg in the socket E. The slide 13 is thus secured to theleg' B of the compass, and by loosening the adjacent set screws 15,,the body bar 10 may be moved longitudinally upon the slide 13 into the desired position. This positionmay be determined by the scale of graduations20. As

soon'as the adjustment is had, the other set screw 15 may be loosenedand the slide 14 extended from thebody bar '10, as shown in Fig.11 a The set screws 15 are of course tightened as soon as the desired adjustment of the slides 13 and 14 is obtained. The scriber section Gr is now secured by means of its stem F in the socket head 18 of the lower slide 14. In use, the knob 19 may be grasped in the fingers and the parts moved into the various desired positions of adjustment, and the knob 19 may be employed for swinging the scriber section G in the operation of drawing an arc, circle or the like.

It is of course understood that various changes and modifications may be made in the details of construction and design of the above specifically described parts of this in vention without departing from the spirit thereof, such changes and modifications being restricted only by the scope of the following claims.

I claim 1. In an extension leg for compasses, the combination with a leg, and a removable scriber section for the leg, of a pair of slidably connected members, means for securing the members in various positions of extension, means for attaching one of said members to said leg in lieu of the scriber section, and means for securing the other member to the scriber section.

2. In an extension leg for compasses, the combination with a leg, and a removable scriber section for the leg, of a pair of slid-- ably connected members, means for securing the members in various positions of extension, a head mounted on one of said members adapted to interchangeably engage said leg, and a head mounted upon the opposite member adapted to interchangeably engage said scriber section.-

3. In an extension leg for compasses, the combination with a leg, and a removable scriber section for the leg, of a body bar having guides on its opposite sides, slides adjustably mounted in said guides and adapted to be extended from the opposite ends of the body bar, means for securing said slides in various positions of extension, an attaching means carried upon the opposite outer ends of said slides adapted for detachable engagement with said leg and said scriber section.

4. In an extension leg for compasses, the combination with a leg, and a removable scriber section for the leg, of an elongated body bar provided with recesses extending longitudinally in the opposite sides thereof, slides mounted in the recesses of the body bar and adapted to extend longitudinally from the opposite ends thereof, means for binding said slides in the recesses. to hold the slides in adjusted position, and heads mounted upon the opposite outer ends of said slides adapted for detachable engagement with said leg and said scriber section respectively.

5. In an extension leg for compasses, the

combination with a leg, and a removable scriber section for the leg, of a body bar substantially rectangular in cross-section and provided with longitudinal extending dove-tailed grooves in the opposite sides thereof, a pair of slides of dove-tail crossscction fitting in said grooves and adapted to be adjusted longitudinally through the bar and extending beyond the opposite ends thereof, set screws threaded in one side of the bar adapted to engage the adjacent edge portion of said slides to bind the latter in adjusted position, and attaching heads mounted upon the opposite outer ends of said slides adapted for engagement respectively with said leg and said scriber section.

6. In an extension leg for compasses, the combination with a leg, and a removable seriber section tl1erefor,-of a body bar providcd in opposite sides With guiding recesses extending longitudinally of the bar, a pair of slides fitting in said recesses and adapted to be extended from the opposite ends of the bar, a scale on the bar cooperating with the slides to determine the positions of adjustments thereof, means carried by the body barfor securing the slides when adjusted, and attaching means carried upon the opposite outer ends of said bar for engagement respectively With said leg and said scriber section.

LOUIS PRICE.

Gopies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. G. 

